Method of interconnecting metal chair rounds and legs



1962 A. FROEDGE 3,058,777

METHOD INTERCONNECTING METAL CHAIR ROUNDS AND LEGS Filed Sept. 15, 1959 United States Patent Filed Sept. 15, 1959, Ser. No. 840,129 1 Claim. (Cl. 297-440) This invention relates to a method of interconnecting metal chair rounds and legs. The invention also relates to the chairs produced by the method. It is contemplated that this invention may have other applications in the fabrication and assembly of chairs, tables, and other items of metal furniture wherein it is desired to provide a secure yet readily releasable connection between hollow tubular metal members.

This invention has as its objective the provision of a new and advantageous method of interconnecting metal chair rounds and legs. A further more specific objective is to provide a method of the character indicated which permits the metal chair parts to be fabricated and then shipped in compact, knocked-down condition to the final assembler who will complete the assembly of the metal frame and attach the back and seat. Additional objects and advantages will be indicated in the following specification.

This invention is shown in an illustrative embodiment in the accompanying drawing, in which- FIGURE 1 is a perspective view of a chair having metal frame members including legs and rounds which have been interconnected by the method of this invention;

FIG. 2, an exploded view of the metal chair members of the chair of FIG. 1, showing the members as they would appear after the back and seat are removed from the chair and with the rounds disconnected from the legs;

FIG. 3, a perspective exploded detail view showing a portion of the chair leg, the connector bushing, and a portion of the chair round, the parts being shown in separated relation for purpose of clarity;

FIG. 4, a view similar to FIG. 3 showing the same parts in separated relation, except that the parts are in section instead of being shown in perspective; and

FIG. 5, a detail perspective view showing the parts of FIGS. 3 and 4 in their interconnected relation.

Turning now to a detailed description of the embodiments shown in the drawing, the chair of FIG. 1 includes a back 10, a seat 11, a pair of metal frame members designated generally as 12 and 13, and a pair of rounds 14 and 15. The frame members 12 and 13 each provide a pair of downwardly extending legs 12a, 12b, and 13a, 13b. These frame members also provide cross-pieces 12c and 130 extending between the upper ends respectively of legs 12a, 12b and 13a, 13b, as well as upwardly extending supports 12d and 13d. The cross-pieces 12c and 130 are adapted for connection to the seat 11, and the upwardly extending supports 12d and 13d are adapted for connection to the seat back 10.

In the preferred embodiment of the present invention, all of the elements comprising frame members 12 and 13 are rigidly connected to form one-piece assemblies. For example, the front legs 12a and 13a can be secured respectively to the forward ends of cross-pieces 12c and 130 by welding, and the rear ends of these cross-pieces can also be secured by Welding to integral members providing the rear legs and the chair back supports, such as the members forming respectively the legs 12b, 13b and the integrally connected supports 12d and 13d.

In practicing the present invention, oppositely-disposed circular openings are formed in the facing sides of each pair of the chair legs, for example, in the front "ice legs 12a, 13a and in the back legs 12b, 13b. 'In the illustration given, these openings are designated by the number 16. Since the metal legs comprise hollow tubes, as indicated more clearly in FIGS. 3-5 for leg 12a, connector bushing 17 can be inserted in the openings 16 as indicated in FIG. 2 and shown more clearly in FIG. 5. As shown in FIGS. 3-5, the connector bushings 17 are hollow, and are dimensioned so as to be slightly longer than the interior diameter of the legs in the vicinity of the openings 16.

As shown more clearly in FIG. 5, the bushings 17 have outer ends providing transversely-extending crown portions 17a which bear against the inner walls of the legs opposite openings 16. Preferably, the outer ends of bushings 17 are closed by the crown portions 17a so that the central portions of the crown are in abutting relation with the inner walls of the legs, as indicated in FIG. 5. Inner ends 17b of bushings 17 are dimensioned and arranged to project inwardly to openings 16, as shown more clearly in FIG. 5. The inner ends 17b are open for receiving the tapered outer end portions of the rounds 14 and 15, such as the tapered end portion 14a of round 14 shown in FIGS. 3-5.

In accordance with the present invention, the side walls of the bushings 17 taper or converge from the open ends 17b towards the closed ends 17a. This provides the interior walls of the bushings with a corresponding taper. Preferably, the inner ends of bushings 17 are dimensioned so as to be snugly received within the openings 16 when fully inserted therein, with the outer ends of the bushings 17a in abutting relation with the opposite inner walls of the legs.

To insure the proper interlocking of the chair rounds with the bushings, it is important to provide the outer ends of the chair rounds, such as ends 14a, with a slightly lesser degree of outward taper than the internal taper of the bushings. For example, the taper of the outer ends of the chair rounds may be 5 to 6, while the internal taper of the bushings approximates 7 to 8, the angle of taper being measured with respect to the horizontal, as the parts are illustrated in the drawing. It is also important that the extreme tip ends of the rounds have an external diameter corresponding to the internal diameter of the inner end portions of the bushing. These parts are so dimensioned and arranged that the end portions of the chair rounds upon being driven into the bushings form a secure but releasable interlock therewith. A few light taps of a mallet is all that is required to seat the ends of the chair rounds within the bushings and establish the tight frictional interlock. If it is desired to separate the parts, one of the legs can be tapped free with a mallet, and the other leg can be separated fgrom the round by tapping the round laterally, and then working the round back and forth while pulling it away from the leg until the frictional interlock is released.

In the assembly of the legs and bushings, the closed ends 1711 of the bushings 17 are preferably connected to the inner walls of the legs by spot welding, as indicated at 18 in FIG. 5. Other suitable securing means can also be used, although probably not as advantageously as spot welding.

In the commercial use of this invention, it is contemplated that the metal frame members, such as frame members 12 and 13, will be formed in one-piece assemblies, the openings 16 will be formed in the legs by any suitable means such as drilling, the bushings 17 will be inserted therein and secured to the legs by spot welding. The metal parts required to fabricate the complete chair will then consist of the four separate pieces shown in FIG. 2. These pieces can be shipped in a compact, knocked-down condition to an assembler of the complete chairs. This may be another manufacturer or an individual purchaser.

I i1 any event, all that is required to form the complete chair is that the rounds 14 and 15 are connected to the frame members 12 and 13 by means of the bushing connectors -17, thereby forming the complete frame simply and quickly without the need for any special tools. The assembly of the chair can then be completed by simply attaching the seat 11'to the cross-pieces 120 and 13c, and the seat back to the supports 12d and 13d. If it is later desired to take the chair apart for compactness in storage or shipping, this can readily be done by reversing the assembly procedure just described.

:While a preferred embodiment has been described in detail in the foregoing specification for the purpose of more clearly illustrating the present invention, it will be apparent to those skilled in the art that many of the details previously described can be varied considerably without departing from the basic principles of this invention.

I claim:

In 'a chair, a pair of oppositely-disposed metal frame members, each of said members providing two downwardly-extending hollow tubular legs, an upwardly-extending support for connection to a chair back, and a cross-piece extending between the upper ends of the legs for connection to a chair seat, all of the elements in each of said frame members being rigidly connected to form a one-piece assembly, the legs of each of said frame members being disposed in paired relation with one of the legs of the opposite frame member, oppositely-disposed circular openings being provided in the facing sides of each pair of said legs, a hollow cylindrical metal connector bushing snugly received Within each of said openings,

said bushings having open inner end portions projecting through said openings, closed outer end portions bearing against the inner walls of said legs opposite said openings, and said bushings tapering interiorly from said open ends toward said closed ends, the closed ends of said bushings having portions thereof fused to the adjacent Walls of said legs, and metal chair rounds having tapered outer ends extending between each pair of said legs, the outer end portions of said rounds being received within said bushings, said outer portions of said chair rounds having a slightly lesser degree of outward taper than the internal taper of said bushings and the extreme tip ends of said rounds having external diameters corresponding to the internal diameters of the inner end portions of said bushings at a spaced distance from said closed outer end portions, the adjacent tapered surfaces of said rounds and said bushings being frictionally interlocked and the said tip end of said rounds being spaced from the closed ends of said bushings, whereby said members are securely connected while being readily disassembled.

References Cited in the file of this patent UNITED STATES PATENTS Jackson Dec. 17, 1907 

